What Is Untap.in and How Do You Play-Test Trading Card Games Online?

Untap.in is a free, browser-based virtual table for play-testing CCG and TCG decks. You build or import a deck, then test it against live opponents worldwide or against an empty seat — no download, install, or patching required. It's the right tool if you want to rehearse lines, test opening hands, or try a brew before buying cards, and you're comfortable managing the rules yourself: Untap.in does not enforce any game's rules, so you play the way you would across a real table.

How to start play-testing

1. Build or import a deck. Search the full card database for any supported game, or paste a plain-text decklist or import one by URL from popular deck-building sites. You can also share your deck with a link.
2. Choose how to test. Open a table or join a game from the public lobby for live multiplayer, or goldfish solo against an empty seat to check opening hands, mulligans, and your lines before a real match.
3. Play and review. Watch live matches, undo a misclick, or play a finished game back turn by turn.

Because the platform doesn't enforce rules, both players track life totals, triggers, and state themselves — the same as sitting across a physical table.

What you can do on Untap.in

• Build decks — full card databases for 40+ games, with plain-text or URL import and shareable links.
• Play live — open a table or join from the public lobby on desktop, tablet, or phone.
• Goldfish solo — test opening hands and mulligans against an empty seat.
• Draft, cube, and sealed — run booster drafts with friends; bots fill empty seats so a pod is always ready.
• Spectate and rewind — watch live matches, undo a misclick, or replay a finished game turn by turn.
• Custom games — upload your own cards (art, text, and whatever fields your game needs) and build decks from them like any published game.

Supported card games

Untap.in supports 40+ games, including:

…and 30+ more.

Common questions

Is it free? Yes — building decks, goldfishing, drafting, and joining live multiplayer games are all free. Optional supporter perks help keep the servers running, and some modes (like Deck vs Deck) are supporter features.

Do I need to download anything? No. It runs in your web browser on desktop, tablet, and phone, and can install as an app straight from the browser.

Can I import a decklist I already have? Yes — paste plain text or import by URL from popular deck-building sites, then start testing immediately.

Can I play my own custom card game? Yes. Upload your own cards and build decks from them exactly like a published game. Since no rules are enforced, a homebrew set behaves the same as anything else on the table — goldfishing or Deck vs Deck is the fastest way to flesh one out.

Untap.in is an independent, fan-built play-testing platform and is not affiliated with, endorsed by, or sponsored by the game publishers whose cards it supports.